Hi Hoggardhigh,
Here's what my research came up with:
At the end of 1939, the Navy ordered 158 examples (serials 2189-2288 and 3073-3130) of the OS2U-2, a new model distinguished primarily by its slightly improved P&W R-985-50 Wasp Junior engine. (The OS2U-1 had used the R-985-48.) Combat versions of the OS2U-2 could also be equipped with a fifty-gallon bullet-proof fuel tank in each outer wing panel. (Although equipped with a CO2 purging system, the main 144-gallon fuel tank was neither armored or self-sealing on the OS2U.) Combat OS2U-2s were also retrofitted with minimal armor protection for the crew.
The OS2U-2 would be assigned to Battle Force to replace the original OS2U-1s or to serve on older Omaha-class cruisers (which, like battleships, had no hangars); others were assigned to fleet auxiliaries (primarily seaplane tenders). The majority, however, were delivered to the Navy's new "inshore patrol squadrons" to patrol US coastal regions and, eventually, the waters surrounding US Pacific island bases. The OS2U was not the perfect aircraft for this mission – for example, the aircraft was never equipped with any form of search radar. But the Kingfisher (as the OS2U was named on 1 October 1941) was reliable, well-built, and relatively inexpensive at a time when the Navy needed as many patrol aircraft as it could afford. On wheels and on floats, OS2Us would serve with inshore patrol squadrons through the end of the war. The Navy also needed advanced landplane and floatplane trainers; here again, the OS2U was not a perfect fit for the job, particularly with its limited visibility from the back seat, but the Navy was hard-pressed to find any suitable aircraft, and Vought had proven an ability to deliver aircraft as promised. The first OS2U advanced trainers were delivered in early 1941. When equipped with pontoons, land-based OS2U-2s used EDO floats, while those aircraft assigned to shipboard duties used the same Vought floats originally mounted on all OS2U-1s; the Navy purchased other OS2U-2s to serve as landplanes only.
I should note that the Vought floats proved a bit too weak in heavy seas and were soon replaced by EDO floats on all versions.
Cheers,
Dana